U.S. Pat. No. 3,845,018 and U.S. Pat. No. 3,897,349 disclose certain acetylene end-capped polyimide oligomers. Moldings prepared from such resin have excellent physical properties which are largely retained at temperatures as high as 316.degree. C. (600.degree. F.).
The polyimides disclosed in these patents must be prepared from aromatic diamines of specific structures to obtain the desired high temperature performance properties. Unfortunately such amines are difficult to synthesize and are expensive.
The synthesis also requires employment of aminoarylacetylenes which are difficult to synthesize and are expensive. As a consequence, the polyimides of U.S. Pat. No. 3,845,018 and U.S. Pat. No. 3,897,349 can be employed only where critical operational requirements can justify unusually high material costs.
For the above reasons, there is a need in the art for polyimides having good high temperature performance properties which can be prepared from polyamines that can be more easily synthesized and be made available at lower cost.